But then, in 2010 award-winning film director Mike Leigh told Spall he wanted him to learn how to paint, in preparation for the role of the great British painter, J.M.W. Turner.

Spall began studying with the accomplished portrait painter Tim Wright. Two years later, the actor was painting a full-size copy of Turner’s masterpiece, Snow Storm - Steam-Boat off a Harbour’s Mouth.

“It was a great thing to do,” Spall says, proudly.

Leigh's film, Mr. Turner - which opens in the UK on 31 October - depicts the final 25 years of the painter’s life when he produced the radical works that are now regarded as a prelude to Impressionism and the abstract art of the 20th century.

"Turner predicted [all this] through his own genius," Spall says, noting that Turner was often derided in his own time.

"I've always had a very free mind when something turns up in the art world that is considered to be nonsense," he says.

Spall's open-mindedness goes back to his adolescent years when he developed a large and varied appetite for all aspects of culture, particularly music.

His first love, he says, was - and still is - Baroque music, recalling lying on his bed, switching between listening to Jimi Hendrix at one moment and Handel's Messiah the next.

Spall's performance as the anarchic, grunting and foul-mouthed Turner has been universally praised. But winning the Best Actor prize at this year’s Cannes Film Festival came as a big surprise to the actor. He happened to be working on his boat in the north of the Netherlands when a car pulled up to whisk him off to Cannes.

His acceptance speech was somewhat impromptu, he says. “I did go on a bit because I had to improvise – but I was just so over the moon.”

Awards, he concludes, “just help to make people more interested in what might be an esoteric subject.”